Fix the crash due to AudioRendererImpl::audio_clock_ being null

media/renderers/audio_renderer_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/renderers/audio_renderer_impl.h"
 
 #include <math.h>
 #include <stddef.h>
 #include <algorithm>
 #include <utility>
@@ skipping 319 matching lines @@
 void AudioRendererImpl::Initialize(DemuxerStream* stream,
                                    CdmContext* cdm_context,
                                    RendererClient* client,
                                    const PipelineStatusCB& init_cb) {
   DVLOG(1) << __func__;
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(client);
   DCHECK(stream);
   DCHECK_EQ(stream->type(), DemuxerStream::AUDIO);
   DCHECK(!init_cb.is_null());
+
+  base::AutoLock auto_lock(lock_);
   DCHECK(state_ == kUninitialized || state_ == kFlushed);
   DCHECK(sink_.get());
 
   // If we are re-initializing playback (e.g. switching media tracks), stop the
   // sink first.
   if (state_ == kFlushed) {
-    sink_->Stop();
-    audio_clock_.reset();
+    // Release the lock while we are stopping the sink to avoid deadlock if the
+    // sink needs to wait for the current Render to finish.
+    auto* sink = sink_.get();
+    base::AutoUnlock auto_unlock(lock_);
+    sink->Stop();
   }
 
-  // Trying to track down AudioClock crash, http://crbug.com/674856.
-  // AudioRenderImpl should only be initialized once to avoid destroying
-  // AudioClock while the audio thread is still using it.
-  CHECK_EQ(audio_clock_.get(), nullptr);
-
   state_ = kInitializing;
   client_ = client;
 
   audio_buffer_stream_ = base::MakeUnique<AudioBufferStream>(
       task_runner_, create_audio_decoders_cb_, media_log_);
 
   audio_buffer_stream_->set_config_change_observer(base::Bind(
       &AudioRendererImpl::OnConfigChange, weak_factory_.GetWeakPtr()));
 
   // Always post |init_cb_| because |this| could be destroyed if initialization
@@ skipping 644 matching lines @@
   // All channels with a zero mix are muted and can be ignored.
   std::vector<bool> channel_mask(audio_parameters_.channels(), false);
   for (size_t ch = 0; ch < matrix.size(); ++ch) {
     channel_mask[ch] = std::any_of(matrix[ch].begin(), matrix[ch].end(),
                                    [](float mix) { return !!mix; });
   }
   algorithm_->SetChannelMask(std::move(channel_mask));
 }
 
 }  // namespace media